Mandrel



ec. 21, 1954 c J L 2,697,386

MANDREL' Filed May 6, 1949 I 2 Sheets-Sheet 1 FIG. I

i INVEN R ATTORNEYS c. J. LANE 2,697,386

MANDREL 2 Sheets-SheetZ Dec. 21, 1954 Filed May 6, 1949 ATTORN EYS United States Patent '0 MANDREL Cliiford J. Lane, Buifalo, N. Y., assignor to 'Daysh'om, Incorporated, :a corporation of New Jersey Application May 6, 1949, SerialNo. 91,657

3 Claims. (Cl. 93-81) This invention rel-ates to mandrels, and more particularly to -'a mandrel construction for use in forming tubes from sheet material.

It has heretofore been proposed to manufacture tubes from sheet material by winding sheets of a width equal to the length of the tube and of a length equal to a multiple of the diameter of the tube on a mandrel with a plurality of rolls, preferably three, in contact with the mandrel at spaced points. By employing sheet material which is thermoplastic, or coated with a thermoplastic cement, the layers of the material are caused to adhere to each other by heating the rolls or the mandrel, or both.

In one form of apparatus heretofore proposed, after the tube is wound on the mandrel, the mandrel is moved axially to clear the rolls and permit removal of the tube. To permit such movement the lower roll is moved away from the mandrel. It is also necessary to disengage the mandrel from the upper rolls and this has heretofore been accomplished by allowing some play in the mandrel support which permits it to move away from the upper rolls when it is not supported-by thelower roll.

The provision of such means for disengaging the mandrel from the upper rolls provides a construction which is accompanied by several disadvantages. One of these is that the mandrel is thus brought out of horizontal a1ignment and when the tube is removed from the mandrel by means which grip the outer surface of the tube, or by means which grip the mandrel and strip the tube therefrom, the misalignment of the mandrel frequently causes jamming.

In the present invention I provide an apparatus of the type heretofore described in which the mandrel is rigidly supported to maintain it in alignment at all times but in which it is capable of moving away from the upper rolls when it is not supported by the lower rolls. The tube receiving portion of the mandrel consists of an inner member and a tubular outer member whose inner diameter is greater than that of the inner member to permit relative movement of the two members. These two members are locked or secured to each other by suitable means to permit this radial relative movement of them but to prevent relative movement axially of the two members. Preferably I provide a tubular outer member having rings or washers inserted in each end so that they fit over inner member with relatively large radial clearance but are constrained axially by suitable locking means. Thus, when the rolls are in their active positions, the outer member is spaced evenly about the inner member at all points of its circumference and is engaged by the rolls. When the lower roll moves away from the mandrel, the outer member moves downwardly on the inner member to space it from the upper rolls.

In the accompanying drawings I have shown one form of the invention. In this showing:

Fig. l is a front elevation of a portion of a tube forming machine;

Fig. 2 is a perspective view of the rolls and mandrel showing the means for moving the mandrel axially to clear the rolls;

Fig. 3 is a longitudinal, sectional view of the mandrel and its support taken on line 3-3 of Fig. 2;

Fig. 4 is a detailed, sectional view of the mandrel support on line 4--4 of Fig. 1;

Fig. 5 is a detailed, sectional view of the mandrel on line 5-5 of Fig. 3; and

Fig. '6 is a detailed, sectional view of the mandrel and rolls takenon line 66-o'f Fig. 1.

Referring to the drawings the machine comprises a suitable "bed or table 2 supported from the floor by legs (not shown). On the table I provide'a pairof side frames 4 and upper rolls 6 and 8 are journalled in suitable bear ings in the side frames. The lower roll 10 is supported in a pivoted frame 12 (see Fig. '2) to move toward and away from the mandrel designated generally by the reference numeral 14. The position of the rolls with respect -'to the mandrel, when the rolls are in operative position, is shown in Fig. 6 of the drawings. Guides 9 havinginner 'surfacesparallel to and slightly spaced from the surface of the mandrel are arranged between the rolls 6, 8 and 10.

The frame '12 is pivoted in the side frames '4 and 16 and a bar or rod '18 connects the two members of the side frame at the front. A suitable operating rod 20 is connected to the rod 18 and the frame is normally "retaiued in raised position by springs 22 which may be anchored on the side frames. Suitable gearing 24 is pro-- vided for the purpose of rotating the rolls and the rolls are provided with commutators 26 by means of which current may be delivered to heating coils 28 within the rolls'to'ra'isethem to the desired temperature.

The mandrel is adapted to be moved to the left in Fig. I of the drawing-s after'the tube has been rolled on 'it and while in this position, a pair of semi-circular gripping members'Sl) are-closed on the mandrel to remove-thetube from the mandrel upon its return movement.

The parts heretofore described are disclosed in more detail -in an application of John Parker Hill Serial "No. 712,027, filed November 23, 1946 (now Patent No. 2,569,856, granted Qeto'ber 2, 1951,) and form no part of my invention, except incombination with the novel mandrel construction to be hereinafter described. As shown, the mandrel is moved by means o'f'an actuating rod 32 which is connected to suitable driving mechanism to reciprocate it when desired. An arm 34 having an L-shaped bracket 36 on its upper end is mounted on this rod. A second arm 38 having a base or foot 40 is secured to the L-shaped bracket 36. As shown, bolts 42 pass through enlarged openings in the vertical arm of the L-shaped bracket 36 and are received in threaded openings in the arm 38. Another bolt 44 passes through a threaded opening in the foot 40 and engages the upper surface of the horizontal portion of the L-shaped bracket. This bolt is retained in adjusted position by a lock nut 46. The upper end of the arm 38 forms a substantially U-shaped yoke 48 and receives the end of a tubular member 50. As shown, the tubular member is flattened as at 52 on each side adjacent its end to be received in the yoke. A bolt 54 extends vertically through the tubular member and is received in a threaded opening 56 at the bottom of the yoke. A second bolt 58 extends across the yoke through the flattened end portions of the member 50 and is retained in place by a nut 60. The bolts 54 and 58 thus form a rigid support for the member 50. An adjusting bolt 62 extends through a threaded opening in the bottom of the yoke in engagement with the member 50 and is retained in adjusted position by means of a lock nut 64.

The member 50, which forms a part of the mandrel assembly but does not form the mandrel proper on which the tubes are wound, receives an arbor 66, the end of the bore in the member 50 being enlarged and the arbor forming a press fit therein as indicated at 68. The arbor extends a desired distance and at an intermediate point it is reduced in cross section as at 70 forming a shoulder 72. Beyond the portion 70 it is again reduced in cross section as at 74 but adjacent its ends it is provided with a portion 76 of the same diameter as the portion 70. A sleeve 78 surrounds the arbor, the sleeve being made of a desired material on which the tube may be rolled. In actual practice I have employed a Bakelite sleeve. The external diameter of the sleeve is equal to the internal diameter of the tube to be formed. The internal diameter of the sleeve is greater than the external diameter of the arbor thereby permitting relative radial movement of the two. Means are provided for preventing axial movement of the sleeve on the arbor. As shown, the internal diameter of the sleeve is increased at each end as indicated at 80. This forms a shoulder 82 adjacent each end of the sleeve. A washer 84 is arranged around the arbor and within the sleeve, the washer abutting the shoulders 72 and 82 at the inner end of the sleeve. At the outer end of the sleeve the washer abuts the shoulder 82 and is retained at its opposite side by snap ring 86 which is received in a groove in the arbor. As shown in Fig. the washer may be provided with spaced cut-out portions 88 forming alternately spaced tabs or fingers 90 which engage the enlarged end portions 80 of the sleeve. The spaces formed by the tabe or fingers permit circulation of air through the mandrel sleeve 78, an important feature contributing to the success of the device. The diameter of the central opening in the washer is greater than the diameter of the portions 70 and 76 of the sleeve providing a clearance 92 which permits downward movement of the sleeve, away from the upper rolls, when the mandrel is unsupported by the lower roll.

In operation, a sheet of material is fed around the sleeve between the rolls with the rolls in the active position shown in Fig. 6 of the drawings. The rolls are heated by supplying current to the commutators 26 and during this portion of the cycle are rotated through the gearing 24. This causes the thermoplastic material to seal and in actual practice the tube is formed of two layers of foil so that a tube is produced of two thicknesses of the foil coated with the thermoplastic. At the end of the tube forming operation, the lower roll is moved downwardly through the operating member 20 and the mandrel operating mechanism is moved axially by rod 32. When the lower roll moves downwardly, the sleeve moves away from the upper rolls a distance equal to the clearance 92 between the openings in the washers 84 and the arbor. This brings the sleeve out of contact with the upper rolls to permit the axial movement, yet keeps the sleeve in a position parallel to the rolls permitting stripping of the tube without jamming due to the misalignment encountered with previous mandrel designs. When the mandrel is in the removed position, and as it starts to return to its operative position, the tube ejecting memher is actuated to cause the sleeve, stripping the tube from the mandrel.

I claim:

1. A floating mandrel comprising an arbor, a tubular member surrounding the arbor and having an internal diameter greater than the external diameter of the arbor, the bore of the tubular member being enlarged adjacent each end forming a shoulder spaced a slight distance from each end of the tubular member, washers arranged in the end portions of the tubular member, the washers having a diameter substantially equal to the enlarged bore of the tubular member and having central openings of larger diameter than the diameter of the arbor to permit radial movement of the tubular member on the arbor, the washers abutting the shoulders to restrain axial movement of them in one direction, and means for restraining axial movement of each of the washers in the other direction.

2. Apparatusin accordance with claim 1 in which the arbor is provided with a shoulder which cooperates with one of the shoulders in the bore of the tubular member to prevent axial movement of one of the washers.

3. Apparatus in accordance with claim 1 in which the arbor is provided with a groove adjacent its ends, and a split ring is arranged in the groove and cooperates with one of the shoulders in the bore of the tubular member to prevent axial movement of one of the washers. 1

References Cited in the file of this patent grips 30 to close about the 

